The field of the present invention relates to air pumps. In particular, air pumps are described herein requiring reduced force to achieve a given pressure.
Many previous air pumps exhibit applied force versus pump stroke distance profiles that increase steeply toward the end of the pump stroke, or are sharply peaked near the end of the pump stroke. The large forces required are often difficult, if not impossible, for a user to achieve. Stroke volumes of many prior pumps are small, so that dozens or even hundreds of strokes are required to pressurize an adequate volume of air (to fill a tire or pressurize a reservoir, for example. It may be desirable to provide a pump wherein the applied force versus pump stroke distance is less steep, less highly peaked, or somewhat flattened; or it may be desirable to provide a pump having an increased stroke volume without a concomitant increase in pump force required.